The serotonergic neural system of the brain has been shown to influence a variety of physiologic functions which manifest themselves in a variety of disorders such as eating disorders, schizophrenia, neuralgia, and addiction disorders; depression, obsessive compulsive disorders, panic disorders, anxiety, sexual dysfunctions caused by the central nervous system and disturbances in sleep and the absorption of food, alcoholism, pain, memory deficits, unipolar depression, dysthymia, bipolar depression, treatment-resistant depression, depression in the medically ill, panic disorder, obsessive-compulsive disorder, eating disorders, social phobia, premenstrual dysphoric disorder, pulmonary hypertension and systemic hypertension.
5-HT receptor modulators e.g., antagonists, partial agonists or agonists, and/or selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine, paroxetine, fluvoxamine, sertraline, lorazepam, imipramine, citalopram, and nortriptyline, may be used for the treatment of the above conditions, as well as for vasodilation, smooth muscle contraction, bronchoconstriction, brain disorders such as vascular disorders such as angina and migraine; and neuropathological disorders including Parkinson's disease and Alzheimer's disease. These compounds are also suitable for the modulation of the cardiovascular system and pulmonary disorders including pulmonary hypertension and pulmonary fibrosis. They also intervene in the regulation of the cerebral circulation and thus represent effective agents for controlling migraine. They are also suitable for the prophylaxis and control of the effects of occurrences of cerebral infarct (Apoplexia cerebri) such as stroke or cerebral ischemia. They are also suitable for the control of disorders of the intestinal tract which are characterized by disturbances of the serotoninergic system and also by disturbances of the carbohydrate metabolism.
Trazodone controls 5-HT actions, and fluoxetine and fluvoxamine facilitate serotoninergic neurotransmission via potent and selective inhibition of serotonin reuptake into presynaptic neurons. 3-chloroimipramine inhibits both 5-HT and norepinephrine reuptake. Other compounds of current interest as antidepressants include zimeldine, bupropion and nomifensine.
Type 2 serotonin inhibitors (5-HT2) mediate the action of several drugs used in treating, e.g., schizophrenia, feeding disorders, perception, depression, migraines, hypertension, anxiety, hallucinations, and gastrointestinal dysfunctions. The 5-HT2A, B or C receptor subtypes show considerable homology at genetic, structural and functional levels, and all are G-protein coupled receptors (GPCRs.) 5-HT2A receptors have been found in high density in the cerebral cortex and in interneuronal regions, as well as (in lower density) in the hippocampus, striatum, other cerebral regions, platelets and vascular and uterine smooth muscle. 5-HT2B receptors are widely distributed in mammalian peripheral tissue, e.g., heart, skeletal and vascular muscle, adipose tissue, intestine, ovary, uterus, testis, liver, lung, pancreas, trachea, spleen, thymus, thyroid, prostate and salivary gland, as well as in the CNS.
It is desired to have selective, high affinity, metabolically stable 5-HT receptor modulators that possess good bioavailability, CNS penetration, and good pharmacokinetic properties, e.g., in vivo.